NM_017807.4:c.40_42delATTinsTTC

Variant names:

• chr14-20454642-AAT-GAA
• NM_017807.4:c.40_42delATTinsTTC
• OSGEP p.Ile14Phe

Variant summary

Our verdict is Likely pathogenic. The variant received 6 ACMG points: 6P and 0B. PS1 PP2 PP3

The NM_017807.4(OSGEP):​c.40_42delATTinsTTC​(p.Ile14Phe) variant causes a missense change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. It is difficult to determine the true allele frequency of this variant because it is of type MNV, and the frequency of such variant types in population databases may be underestimated and unreliable. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Another nucleotide change resulting in the same amino acid substitution has been previously reported as Pathogenic in ClinVar.

• Frequency: Genomes: not found (cov: 33)
• Consequence: OSGEP NM_017807.4 missense
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 8.29
• Publications: 0 publications found

Genes affected

OSGEP (HGNC:18028): (O-sialoglycoprotein endopeptidase) Predicted to enable N(6)-L-threonylcarbamoyladenine synthase activity and metal ion binding activity. Involved in tRNA threonylcarbamoyladenosine modification. Located in cytoplasm; nuclear speck; and plasma membrane. Part of EKC/KEOPS complex. Implicated in Galloway-Mowat syndrome 3. [provided by Alliance of Genome Resources, Apr 2022]

APEX1 (HGNC:587): (apurinic/apyrimidinic endodeoxyribonuclease 1) The APEX gene encodes the major AP endonuclease in human cells. It encodes the APEX endonuclease, a DNA repair enzyme with apurinic/apyrimidinic (AP) activity. Such AP activity sites occur frequently in DNA molecules by spontaneous hydrolysis, by DNA damaging agents or by DNA glycosylases that remove specific abnormal bases. The AP sites are the most frequent pre-mutagenic lesions that can prevent normal DNA replication. Splice variants have been found for this gene; all encode the same protein. Disruptions in the biological functions related to APEX are associated with many various malignancies and neurodegenerative diseases.[provided by RefSeq, Dec 2019]

APEX1 Gene-Disease associations (from GenCC):

• amyotrophic lateral sclerosis

  Inheritance: AD Classification: LIMITED Submitted by: Ambry Genetics

ACMG classification

Our verdict: Likely_pathogenic. The variant received 6 ACMG points.

• PS1: Transcript NM_017807.4 (OSGEP) is affected with MISSENSE_VARIANT having same AA change as one Pathogenic present in ClinVar.
• PP2: Missense variant in the gene, where a lot of missense mutations are associated with disease in ClinVar. The gene has 15 curated pathogenic missense variants (we use a threshold of 10). The gene has 2 curated benign missense variants. Gene score misZ: 0.75927 (below the threshold of 3.09). Trascript score misZ: 1.0429 (below the threshold of 3.09). GenCC associations: The gene is linked to Galloway-Mowat syndrome 3, Galloway-Mowat syndrome.
• PP3: No computational evidence supports a deleterious effect, but strongly conserved according to phyloP

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_017807.4. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	OSGEP	NM_017807.4	MANE Select	c.40_42delATTinsTTC	p.Ile14Phe	missense	N/A	NP_060277.1	Q9NPF4

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	OSGEP	ENST00000206542.9	TSL:1 MANE Select	c.40_42delATTinsTTC	p.Ile14Phe	missense	N/A	ENSP00000206542.4	Q9NPF4
	OSGEP	ENST00000956270.1		c.40_42delATTinsTTC	p.Ile14Phe	missense	N/A	ENSP00000626329.1
	OSGEP	ENST00000883550.1		c.40_42delATTinsTTC	p.Ile14Phe	missense	N/A	ENSP00000553609.1

Frequencies

GnomAD3 genomes Cov.: 33

We have no GnomAD4 exomes data on this position. Probably position not covered by the project.

GnomAD4 genome Cov.: 33

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
PhyloP100		8.3

Splicing

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

MaxEntScan Visualizer can be used to analyze the impact of this mutation on the neighboring sequence.

Other links and lift over

hg19: chr14-20922801;